The ruling was in response to a battle between the FCC and Fox Broadcasting over so-called fleeting obscenities. The FCC had decided in 2004 that TV stations could be fined for indecency violations in cases when, during a live broadcast, an obscenity went out over the air. The decision came after Fox aired awards shows in 2002 and 2003 in which swearing by Cher and Nicole Richie was not bleeped in time by the network. Later, U2 front-man Bono put NBC in the hot seat with the FCC for swearing during the Golden Globes telecast.

In Richie's case, she was talking about her experience working on a farm as part of a reality show and complained quite vividly about the challenges of getting manure out of a Prada purse.

While the FCC never fined Fox, the network took issue with the agency's laying the groundwork for future fines and challenged the rules in court.

The court also took issue with how the FCC enforced its regulations with regards to various television shows including the ABC drama "NYPD Blue." The FCC concluded some language in an episode of the cop drama was patently offensive but allowed other expletives.

Such vagaries in enforcement at times confused networks. The court's decision notes that Fox once chose not to rerun an episode of its comedy "That 70s Show" that dealt with sexual issues even though the episode had not been targeted for indecency in the show's first airing.

While the decision was based on a case involving celebrities swearing on live television, the FCC's indecency rules have also worried broadcasters when it comes to airing more serious content such as the movie "Saving Private Ryan" and a documentary on the Sept. 11 attacks that included swearing by firefighters in the midst of rescue efforts.

In a statement, Fox said, "we are extremely pleased with the decision handed down today by the 2nd Circuit. We have always felt that the government’s position on fleeting expletives was unconstitutional."

The FCC had no immediate comment on the court's decision. It can appeal the ruling to the Supreme Court, which could decide to hear the case or pass on it. It can also rewrite its indecency rules.

For now, the FCC's rules are no longer on the books, a move that was cheered by some media watchdogs.

“The score for today’s game is 1st Amendment one, censorship zero," said Andrew Schwartzman, senior vice president of the Media Access Project, in a statement. "The next stop is the Supreme Court, and we’re confident that the justices will affirm this decision.”

Fox wasn't the only network fighting the FCC over its indecency rules. CBS has been in a long-running battle with the agency since Janet Jackson's breast was exposed during the network's coverage of the Super Bowl in 2004.